Impact of Bariatric Surgery on the Pharmacokinetics Parameters of Amoxicillin

  • Marina Becker Sales RochaEmail author
  • Gilberto De Nucci
  • Francisco Ney Lemos
  • Rodrigo Feitosa de Albuquerque Lima Babadopulos
  • Andrea Vieira Pontes Rohleder
  • Francisco Vagnaldo Fechine
  • Natalícia J. Antunes
  • Gustavo D. Mendes
  • Demetrius Fernandes do Nascimento
  • Manoel Odorico de Moraes
  • Maria Elisabete Amaral de Moraes
Original Contributions



Bariatric surgery leads to several anatomo-physiological modifications that may affect pharmacokinetic parameters and consequently alter the therapeutic effect of drugs, such as antibiotics. The pharmacokinetics of oral amoxicillin after Roux-en-Y gastric bypass (RYGB) surgery is unknown.


The objective of this study was to evaluate the impact of bariatric surgery on the pharmacokinetics of amoxicillin.


This study was performed as a randomized, open-label, single-dose clinical trial, with two periods of treatment, in which obese subjects (n = 8) received an amoxicillin 500 mg capsule orally before and 2 months after the RYGB surgery. The amoxicillin plasma concentration was determined by liquid chromatography coupled to mass spectrometry (LC-MS/MS).


After the surgery, the mean weight loss was 17.03 ± 5.51 kg, and mean body mass index (BMI) decreased from 46.21 ± 2.82 to 38.82 ± 3.32 kg/m2. The mean amoxicillin area under the plasma concentration versus time curve from time zero to the time of the last quantifiable concentration (AUC0–tlast) increased significantly (3.5-fold); the maximum plasma concentration (Cmax) increased 2.8-fold after the bariatric surgery. No correlation was found between amoxicillin absorption, BMI, and weight loss percentage.


The alterations observed in the amoxicillin pharmacokinetics suggest that obese subjects included in this trial had a substantially increase in amoxicillin systemic exposure after RYGB surgery. However, despite this increase, its exposure was lower than the values reported for non-obese volunteers.

Trial Registration

Identifiers: NCT03588273


Amoxicillin Bariatric surgery Pharmacokinetics Obesity Gastric bypass 



This work was supported by the Brazilian Ministry of Science and Technology and the National Council for Scientific and Technological Development through the public announcement PQ10/2011—productivity in research—PQ-2011 (grant number 309228/2011-5).

Compliance with Ethical Standards

The study was approved by the institutional review board (IRB) of the Federal University of Ceará (number 255.607) and the Scientific Committee of the Hospital General Dr. César Cals.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed Consent

Informed consent was obtained from all individual participants included in the study.

Conflict of Interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Marina Becker Sales Rocha
    • 1
    Email author return OK on get
  • Gilberto De Nucci
    • 2
  • Francisco Ney Lemos
    • 3
  • Rodrigo Feitosa de Albuquerque Lima Babadopulos
    • 3
  • Andrea Vieira Pontes Rohleder
    • 1
  • Francisco Vagnaldo Fechine
    • 1
  • Natalícia J. Antunes
    • 2
  • Gustavo D. Mendes
    • 4
    • 5
  • Demetrius Fernandes do Nascimento
    • 1
  • Manoel Odorico de Moraes
    • 1
  • Maria Elisabete Amaral de Moraes
    • 1
  1. 1.Clinical Pharmacology Unit, Drug Research and Development CenterFederal University of Ceara (UFC)FortalezaBrazil
  2. 2.Faculty of Medical Sciences, Department of PharmacologyState University of CampinasCampinasBrazil
  3. 3.Unit of Bariatric SurgeryHospital General Dr. César CalsFortalezaBrazil
  4. 4.Department of PharmacologyMetropolitan University of SantosSantosBrazil
  5. 5.Department of Pharmacology, Faculty MedicineSão Leopoldo MandicCampinasBrazil

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